PARSIPPANY, N.J.--(BUSINESS WIRE)--Apr 15, 2010 - Results of the
first randomized, head-to-head comparison of direct thrombin
inhibitors (DTIs) in patients with heparin-induced thrombocytopenia
(HIT) were presented at the Hemophilia & Thrombosis Research
Society 2010 Scientific Symposium in Chicago, Illinois on April 15.
The PREVENT-HIT study found that desirudin warrants further
investigation as an alternative treatment for thrombosis
prophylaxis in surgery patients with HIT.

The study compared desirudin with argatroban, the current
standard of care. In the study, no thrombosis or major bleeds
occurred in patients who received desirudin, and fewer dose
adjustments were required for patients receiving desirudin compared
with those receiving argatroban. In addition, the cost of treatment
with desirudin was about one-fifth the cost of treatment with
argatroban.

Desirudin, or Iprivask®, is the first
direct-thrombin inhibitor (DTI) approved in the United States by
the Food and Drug Administration (FDA) for subcutaneous
administration. It is approved for the prevention of deep vein
thrombosis (DVT), which may lead to pulmonary embolism in patients
undergoing elective hip replacement surgery. It had not previously
been studied in patients with HIT.

PREVENT-HIT is a randomized trial comparing fixed-dose,
subcutaneous (SC) desirudin with adjusted-dose, intravenous (IV)
argatroban in patients with clinically suspected heparin-induced
thrombocytopenia (HIT). The study concluded that the low rate of
thrombotic events in a population at high risk confirms the
usefulness of DTIs for patients with HIT. It also found that
subcutaneous desirudin at fixed doses of 15 or 30 mg every 12 hours
was effective in patients with suspected HIT. The cost of desirudin
($1,750) was about one-fifth the cost of argatroban ($8,250).

In addition, there was the need for only one dose adjustment
throughout the entire trial in patients randomized to desirudin, as
compared to an average of 3.8 dose adjustments per patient in
subjects randomized to IV argatroban.

“HIT can be a serious clinical issue in the cardiac
surgery patient,” said Steven W. Boyce, MD, Surgical
Director, Heart Failure and Transplant Program, Washington Hospital
Center, Washington, DC. “In our study we found that the cost
and ease of administration of subcutaneous desirudin could make it
an attractive alternative to IV argatroban in patients with
suspected HIT. I look forward to further study of desirudin's use
as a DTI for thrombosis prophylaxis.”

“We are evaluating the impact of these significant data on
further desirudin investigations,” said Dawn Bell, PharmD,
Senior Vice President and General Manager of Canyon
Pharmaceuticals, desirudin's manufacturer. “These study
results build on the potential for Iprivask to advance patient
care.”

Study Design

The study was a randomized, open-label, exploratory study
comparing fixed-dose, SC desirudin vs. adjusted-dose, IV argatroban
in 16 patients with clinically suspected HIT. Patients were
randomized to desirudin 15 or 30 mg SC every 12 hours or IV
argatroban in a 1:1 ratio. The primary endpoint was a composite of
new or worsening thrombosis requiring discontinuation of study
drug, amputation, or death from any cause. Secondary endpoints
included major and minor bleeding and pharmacoeconomics. Cost of
drug therapy was estimated using wholesale acquisition costs. Most
patients in the study had developed HIT after vascular or cardiac
surgery.

Results

Of 16 patients randomized, heparin antibody tests were positive
in 11 (nearly 70%) with similar frequency between the groups. The
mean baseline platelet count was 121,000/mm3 vs.
88,000/mm3 in the argatroban and desirudin groups,
respectively. The mean initial dose of argatroban was 1.6
micrograms/kilogram per minute (mcg/kg/min). Of the
desirudin-treated patients, 7 of 8 received 15 mg SC every 12
hours. No patients in either group died or required amputation. One
argatroban patient developed new thrombosis, but continued on
argatroban therapy. No patients in the desirudin group developed
thrombosis. Major bleeding occurred in 2 of 8 argatroban patients
vs. 0 of 8 desirudin patients. Each group had one minor bleed.
Argatroban required dose-adjustment an average of 3.8 times per
patient, while desirudin was adjusted one time during the entire
study (from 15 to 30 mg SC every 12 hours). The mean cost of drug
therapy was $8,250 for argatroban compared with $1,750 for
desirudin.

About Canyon PharmaceuticalsTM

Canyon PharmaceuticalsTM is a privately-held
specialty biopharmaceuticals company focused on delivering
innovative therapeutic solutions that target important cellular
pathways in thrombosis and tumor growth. Canyon holds exclusive
world-wide rights to desirudin, a subcutaneous (SC) recombinant
direct thrombin inhibitor (DTI), and to pegmusirudin, a pegylated
recombinant DTI with a longer duration of action than
desirudin.

This press release contains forward-looking statements, which
involve risks and uncertainties within the meaning of the Private
Securities Litigation Reform Act of 1995. There can be no assurance
that actual results will not differ materially from the
forward-looking statements discussed in this press release.